Bandpass Filter Design using the Square Loop Resonator on 3 GHz Frequency for Radar Applications

In recent times, there have been a lot of researches that carry out the development of microstrips as a medium for designing antennas and filters. One form of microstrip development in this research is a filter in radar applications. Designing and realizing a bandpass filter that works at a frequency of 3.0 GHz with the square loop resonator method and analyzing the performance of a bandpass filter that has been designed to have good characteristic values and according to the desired specifications are the objectives of this research. The novelty of research from the square loop resonator method is the resulting eleptic response, narrow bandwidth and small dimensions. Thus, the square loop resonator is the method proposed in this research. The result of this research is to produce a filter response measurement on a vector analyzer. The findings obtained are a bandwidth widening of 30 MHz and a shift in the center frequency of 60 MHz from the original design of 3 GHz to 3.06 GHz. In the simulation results via High Frequency Structure Simulator (HFSS), the return loss (Sll) value is -29.6dB and the insertion loss (S21) value is -0.8dB, while based on the measurement results, the return loss (Sll) value is -22.3dB and the insertion loss value (S21) of -3.05dB.